Apparatus for coating fluorescent lamps



Dec. 28, 1943. c. ALBRIGHT APPARATUS FOR COATING FLUORESCENT LAMPS Filed Sept. 4, 1941 2 Sheets-Sheet 1 Charles L Albrigh LINVENTQR.

- ISM-m ATTOENEY Dec. 28, 1943. c. L. ALBRIGHT APPARATUS FOR COATING FLUORESCENT LAMPS 2 Sheets-Sheet 2 Filed Sept. 4, 1941 Charl e s .Al brighlglNvENTox ATTOR N EY Patented Dec. 28, 1943 2,337,740 APPARATUS FOR COATING FLUORESCENT LAMPS I CharlesL'. Albright, Beverly,

Sylvania Electric Products Inc.,

of Massachusetts Mass.. assignor to a corporation Application September 4, 1941, Serial No. 409,496

4 Claims.

This invention relates to fluorescent lamps and more particularly to apparatus for the coating thereof.

An object of this invention is to provide an apparatus for coating elongated tubular bulbs with a luminescent solution.

Another object is to provide an apparatus which will lend itself to high speed production methods.

A further object is to include in such an apparatus means for washing said bulbs before the application of th luminescent solution.

Further objects, advantages and features will be apparent from the following specification taken in coniunction with the accompanying drawings in which:

Figure 1 is a perspective view of the bulb coating apparatus.

Figure 2 is a diagrammatic perspective view of the actuating mechanism.

Figure 3 is a detail of the nozzle assembly.

Figure 4 is a diagrammatic perspective view of the indexing means.

In the manufacture of fluorescent lamps a coating of luminescent material is applied to the inner walls of th elongated bulb and is then dried before the coated bulb is baked. Before the coating is applied it is desirable to insure the cleanliness of the walls of the bulb by flushing it.

As shown in Figure 1, the apparatus of this invention consists of an elongated conveyor mounted on the I beam iron supports I. This conveyor consists of a pair of endless chains 2 with the plurality of clips 3 attached thereto. These chains move about the sprocket wheels 4 which are driven by the drive shaft 5. Mechanism for indexing thedrive shaft 5 is shown in Figure 4. Shaft 5 is intermittently partially totated through the action of constantly rotating shafts 25, 68 and 69, driven by motor 23 through bevel gear connections. Shaft 69 carries an index arm and index pin H. Pin ll engages peripheral recesses 12, in index wheel 13 fixed on shaft 5. Shaft 5 is held in indexed position by spring finger I4 which engages recesses 12. The bulbs are loaded on the apparatus being positioned with respect to height with the disc l9 atop th shaft 5 as a guide, sprayed with a cleaning solution, coated with a luminescent solution and passed through a series of drying steps.

The bulb 6 is shown at the station at which the bulbs are washed with a quantity of the solvent used in preparing the vehicle for the suspension of the luminescent material. Thus, for example, if butyl acetate were the solvent used as is the case here, th bulbs would be washed with butyl acetate, The butyl acetate flows from the reservoir 1 through the line 8 into the bulb. This flow is controlled by the valve 9 actuated by the solenoid l0.

Two or three stations are permitted to intervene between th bulb washing and the bulb coating positions in order that the excess butyl acetate may drain off and that remaining on the walls of the bulb may dry. At the station at which the bulb II is located, the bulb is coated with a solution of luminescent material. The flow of coating solution from the nozzle I2 is controlled by the valve l3 which is actuated by the solenoid I4. The coating solution reservoir is not shown but may be located above the apparatus similar to the bulb washing reservoir and connected to the line l5.

The remainder of the cycle is devoted to drying the bulb. This is accomplished by causing the bulbs to pass directly beneath an elongated drying chamber which consists of a chamber [6 having a pair of fans I1 mounted on the top thereof to draw in the air and a plurality of holes IS in the bottom thereof, so located that the bulbs will be in register therewith at the several drying stations. The chamber l6 is partly in section to show holes l8.

The excess butyl acetate which drains from the bulbs as they are washed passes through the filter 20 in the recovery reservoir 2| and is pumped from there back up into the reservoir 1 through the pump shown in Figure 2 and the connecting line 66. The excess coating solution which drains from the bulbs runs down the inclined trough 22 and may be collected and reclaimed therefrom.

Figure 2 shows the mechanism which actuates I the washing and coating nozzles. The motor 23 through the belt 24 drives the cam shaft 25 with the cam 25 thereon. The cam follower 21 on the arm 28, following the contour of the cam 26 provides the means through which the washing nozzle and the coating nozzle are brought down to the top of each bulb after the machine has indexed to the washing and coating stations and are withdrawn therefrom to permit the indexing of the machine.

Movement of the arm 28 to the left is transmitted through the rocker 29, pivoting about the shaft 30, into the downward movement of the shaft 3|. The cross bar 32 is mounted atop the shaft 3| and the shafts 33 and 34 project upward- 1y from the ends thereof. The arm 35 is mounted atop the shaft 33 and the arm 36 is mounted atop the shaft 34.

The lines 31 and 38 are flexible thereby permitting the valve and nozzle washing assembly on the one hand and the coating nozzle assembly on the other hand to be moved downwardly by the downward movement of the shafts 33 and 34 transmitted thereto through the arms 35 and 36 respectively. It is in this down position that the washing nozzle 39 and the spraying nozzle I2 are located in washing and spraying relationship respectively with the bulbs.

The spring 48 suspended between the fixed support 61 and the cross bar 32 serves as the means through which the upward movement of the washing and coating nozzlesis assured in order to permit the indexing of the machine. When the shaft moves downwardly, the cross bar 32 also moves but the support 61 remains fixed thereby causing the spring to expand. The expanded spring will .exert a tension sufficient to accomplish the withdrawal of the nozzles 39 and I2 as soon as the contour of the cam 26 so permits. A firm positive cam contact at all times is thereby assured.

As was pointed out in the description of Figure 1, the valves 9 and I3 are energized by the solenoids I and I4 respectively. The circuit through these solenoids is normally open and is closed only when their respective nozzles have dropped down to perform the washing and coating operations respectively. These intermittent periods of actuation are controlled primarily by the mercury switch 42 adjacent the cam operating assembly. The switch 42 is mounted on the arm 43 which is fixed to the shaft 44. The movement of this shaft 44 is governed by the contour of the cam 26 through the cam follower 45 On the connecting link 46. Thus when the cam operating mechanism causes the nozzles 39 and I2 to move into operating relationship to the bulbs, it at the same time closes the circuit through the mercury switch 42 to thereby energize the solenoids I0 and I4 respectively.

There is however a safety check on the actuation of the solenoids in order to prevent their energization when there is no bulb at the washing or at the coating station. The mercury switch 42 is connected to the solenoids Ill and I 4 through mercury switches 41 and 48 respectively. The circuit through these switches is normally open and is closed when a bulb moving from the station immediately preceding the nozzle 39 in one case and the nozzle I2 in the other strikes against the resilient clip 49 on the outer end of the rockr arm 50 in the case of the switch 4'! and the rocker arm in the case of the switch 48. These arms 59 and 5| are pivotally mounted on the supports 52 and 4| respectively. When a bulb strkes the resilient clips 49 it will push the clips back and cause the rocker arms 50 and 5l'on which the switches 41 and 48 respectively are mounted to swing sufiiciently about their respective DivOtS to close the circuit t.1eiet..;r-.u;h and thus energize the solenoids I0 and [4. Thus in cases w;.ere no bulb is present the circuit tl:rough the switch 41 or the switch 48 or both, will remain open and the solenoids I0 and/or I4 will not be energized. The wiring connection between these switches and the solenoids has been omitted in order to more clearly illustrate the apparatus.

Figure 3 shows the coating nozzle assembly. The bulb washing nozzle has not been more completely illustrated for the reason that since it is not necessary to take the degree ofcare and accuracy in washing as it is in coating, any suitable regular nozzle may be used for washing.

, bulbs to the next The bulb coating nozzle I2 consists of the cylindrical chamber 53 into which the coating solution flows from the line 38, the solution deflector plug 54 and the plug 55 on the rod 56 and the metallic bellows 51 concentric with the rod 56 and within the chamber 53 at a point where the rod 56 passes therethrough. The rod 56 is fixed to the arm 36 which is in turn fixed to the top of the shaft 34, The arm 58 pivots on the stud 59 projecting from the shaft 34 and has the cylindrical chamber 53 fixed to one end and the adjustable screw 60 located at the other end.

Since the rod 56 is fixed to the arm 36 which is in turn fixed to the shaft 34, the rod 56 will drop down the same distance as shaft 34. However, the cylindrical chamber 53 will drop down slightly further. By adjusting the screw 60, the chamber 53 will drop with the shaft 34 and the rod 56 until the screw 60 strikes the support M. The chamber 53 will then move down with the rod 56 and further than the rod 56 so that the floor of the chamber 53 will disengage itself with the plug 55 which normally seals the floor of the chamber to prevent the flow of coating solution therefrom. The screw 60 is adjusted so that not only will the plug 55 be drawn up enough to permit passage of the coating solution but also the solution deflector plug 54 will be drawn up sufiiciently close to the bottom of the cylindrical container 53 to deflect the coating solution onto the walls of the bulb at the desired angle.

The tension on the spring 6|, created by the cylindrical chamber 53 moving downwardly further than the arm 36, is sufiicient to draw the chamber 53 back up to its normal position with the plug 55 sealing the floor thereof after the coating operation has been completed and the coating nozzle assembly'has withdrawn itself to permit the indexing of the machine to move the station.

What I claim is:

1. Apparatus for coating elongated bulbs with a solution of luminescent material, said apparatus comprising: means for supporting said bulbs in a vertical position; a carrier for said means movable through a series of indexing steps; a. plurality of stations to which said carrier indexes; a washing nozzle having its operative position above and substantially in register, with an end of one of said bulbs at one of said stations; and a nozzle for coating solution having its operative position above and substantially in register, with an end of one of said bulbs at another of said stations.

2. Apparatus for coating a solution of luminescent material, said apparatus comprising: means for supporting said bulbs in a vert-cal position; a carrier for said means movable through a series of indexing steps; a plurality of stat-ons to which said carrier indexes; a washing nozzle having its operative posit.on above and substantially in register, with an end of one of said bulbs at one of said stations; a nozzle for coating solution having its operative position above and substantially in register, with an end of one of sad bulbs at another of said stations; and means for moving said washing and coating solution nozzles into washing and coating relationship respectively with said bulbs.

3. Apparatus for coat.ng elongated bulbs with a solution of luminescent material, said apparaelongated bulbs with tus comprising: means for supporting said bulbs in a vertical position; a carrier for said means movable through a series of indexing steps; a plurality of stations to which said carrier indexes; a washing nozzle having its operative position above and substantially in register, with an end of one of said bulbs at one of said stations; a nozzle for coating solution having its operative position above and substantially in register, with an end of one of said bulbs at another of said stations; valving means for said washing nozzle; valving means for said coating nozzle; and electrical means for actuating both of said valving means.

4. Apparatus for-coating elongated bulbs with a solution of luminescent material, said apparatus comprising: means for supporting said bulbs in a vertical position; a carrier for said means movable through a series of indexing steps; a

plurality of stations to which said carrier indexes; a washing nozzle having its operative position above and substantially in register, with an end of one of said bulbs at one of said stations; a nozzle for coating solution having its operative position above and substantially in register, with an end of one of said bulbs at another of said stations; valving means for said washing nozzle; valving means for said coating nozzle; electrical means for actuating both of said valving means; automatic means for preventing the electrical actuation of said washing nozzle valving means when a bulb is not in register with said washing nozzle; and automatic means for preventing the electrical actuation of said coating nozzle valving means when a bulb is not in register with said coating nozzle.

CHARLES L. ALBRIGHT. 

